TOO MANY MOUTHS (TMM) is a gene which has been shown to regulate cell fate and control cell division in the plant leaf epidermis. TMM encodes a leucine rich repeat-receptor like protein (LRR-RLP) which has putative function as a signal transducing factor in the cell to cell signaling pathway involved in controlling proper spacing of stomata! initials throughout the leaf. This gene has been shown to be widely conserved across species of land plants ranging from bryophytes to angiosperms. Curiously, although this gene is highly conserved, stomata! installation pathways vary considerably across these species. Leaf development in both Arabidopsis and monocot grasses has been well characterized, and contrasting stomata! development pathways have been identified between them. Dioscorea bulbifera is a basal member of the monocot family, but this species forms broad leaves similar to many eudicot species. Stomata! development in this species retains some features characteristic of grass installation pathways such as few to no secondary asymmetric divisions of meristemoids. However, new epidermal cell formation occurs by fill-in between leaf veins, more closely resembling broad leaf eudicot development. A TMM ortholog has been isolated in this species and phylogenetic analysis of the sequence may help to place the signals controlling stomata! proliferation in Dioscorea bulbifera into evolutionary perspective.

Les Dioscorea cultivées, dont la reproduction sexuée est aléatoire, sont multipliées essentiellement par voie végétative, ce qui entraîne la dissémination dagents pathogènes dans les plantations, provoquant une baisse de rendement et de qualité des récoltes. Dans ces conditions, les besoins en semences sont rarement comblés et les possibilités dextension de la culture restent limitées. En effet, devant une demande quantitative toujours croissante et qualitative de plus en plus restrictive, les techniques classiques encore employées aussi bien pour la multiplication que pour lamélioration de la production des végétaux sont relativement lentes. En revanche, les opportunités offertes par les cultures de tissus peuvent remédier efficacement aux insuffisances et offrir des améliorations irréalisables par les autres méthodes. La multiplication en alternance par bourgeonnement axillaire à partir de nuds pendant 28 semaines et par mise en germination des microtubercules découpés pendant 16 semaines peut remédier à cette situation. Plusieurs facteurs peuvent avoir un impact sur lefficacité de cette approche: la présence ou labsence de régulateurs de croissance, la teneur en saccharose ou en éléments minéraux du milieu de culture. Dans le cadre de cette étude, les tests réalisés ont montré une formation plus précoce du tubercule en présence de polyamines et dacide jasmonique. Si les teneurs en polyamines endogènes et leur métabolisme sont significativement affectés par les polyamines exogènes, les modifications des teneurs en polyamines endogènes, quant à elles, ne peuvent être directement corrélées avec la formation du tubercule. Un retard dans la formation des tubercules lors dune réduction de la teneur en sucre du milieu de culture a aussi été constaté. Ce retard dans nest pas lié à une réduction de losmolarité du milieu de culture, comme nous avons pu le montrer en remplaçant partiellement le saccharose par du sorbitol. La putrescine et ses précurseurs larginine et lornithine favorisent aussi le développement des tubercules, ceux- ci sont plus longs et plus lourds lorsque ces composés sont ajoutés au milieu de culture à faible concentration. Une augmentation de la teneur endogène en putrescine et en auxine a été observée dans ces conditions. Laddition dacide jasmonique a un effet similaire. Une réduction du développement des tubercules est, par contre, observée en présence dune teneur en saccharose réduite. La réduction de la teneur en sucre dans le milieu de tubérisation a aussi un effet négatif sur la germination ultérieure des microtubercules. Pour pouvoir utiliser les microtubercules comme semences, il faut être assuré dun taux de germination élevé et dun stockage possible. Les microtubercules récoltés après 9 mois de culture et transférés sur un nouveau milieu sans régulateur de croissance germent très rapidement. Aucune dormance nest observée. Les microtubercules peuvent aussi être stockés pendant au moins 18 semaines. Les meilleures conditions pour une germination élevée sont une conservation à lobscurité, sous ± 50% dhumidité relative et à 25°C. Une période de dormance secondaire sinstalle une fois le stockage en cours qui varie entre 20 et 28 semaines respectivement pour les microtubercules les plus rapides et les plus lents. Seuls les tubercules de taille supérieure à 350 mm devront être utilisés pour la germination in vitro ou ex vitro.

L’igname (Dioscorea spp) est un aliment de base de plus de 100 millions de personnes en Afrique. L’objectif de cette thèse était d'étudier la diversité génomique de l'igname, comprendre les bases génétiques de sa domestication, et d'étudier son adaptation à différentes zones climatiques. L’étude du processus de domestication de l’igname a été menée par une approche de génomique comparée entre l’espèce cultivée D. rotundata et deux espèces sauvages apparentées D. praehensilis et D. abyssinica, en utilisant des données de séquençage NGS génomique. Nous avons mis en évidence des sélections fortes de gènes de la voie de biosynthèse de l’amidon. Des gènes impliqués dans la morphologie des tubercules ou l’aptitude au phototropisme, ainsi que des gènes du complexe NADH deshydrogenase ont également été identifiés comme sélectionnés durant la domestication. Ce même complexe NADH-DH a également été identifié lors de la recherche de gènes associés à la distribution d’une collection d’ignames selon la variabilité climatique. Nous avons aussi créé la première banque de novo d’éléments transposables (ET) de l’igname. L’étude que nous avons menée sur les éléments répétés (ER) du génome de l’igname nous a permis d’identifier une forte corrélation entre la variabilité des abondances relatives d’un grand nombre d’ERs et la variabilité climatique. Enfin, nous avons pu proposer une hypothèse quant à l’origine de l’igname cultivée D. rotundata. La domestication de l'igname dériverait de l'espèce inféodée au milieu forestier, D. praehensilis. Ces résultats remettent en cause l’hypothèse d’une origine stricte en zone de savane pour les espèces cultivées et l’agriculture en Afrique de l'Ouest. / Yam (Dioscorea spp) is a major staple for more than 100 million people in Africa. The main objectives of the present PhD project were to study yam genomic diversity, its domestication, and to characterize the genomic determinism of its adaptation to different climatic zones. We investigated the genetic basis of yam domestication in a comparative genomic approach between the cultivated species D. rotundata and two wild close relatives D. praehensilis and D. abyssinica, by exploiting NGS sequencing data. We demonstrated that genes from the starch biosynthesis were selected during yam domestication. Genes related to tuber morphology or phototropism ability, as well as genes of the NADH dehydrogenase complex were also under selection. The same NADH-DH complex was also identified when assessing adaptation to climate variability. We also created the first de novo database of yam transposable elements (TEs). The study we performed on these repeat elements (REs) highlighted a strong correlation between the variability in relative abundances of numerous REs and climatic variability. Finally, we were able to propose an hypothesis on the origin of the cultivated yam D. rotundata. Our hypothesis identifies the origin of yam in the forest areas, with the species D. praehensilis as the putative progenitor. Our results question the generally admitted hypothesis of savannah origins for crops and agriculture in Africa.

Made available in DSpace on 2015-04-22T22:17:26Z (GMT). No. of bitstreams: 1 Antonia Paiva Teixeira.pdf: 430157 bytes, checksum: d5512cf8160a1460ce30ab984f83a8a0 (MD5) Previous issue date: 2011-02-21 / Fundação de Amparo à Pesquisa do Estado do Amazonas / The aim of this study was to evaluate the potential of purple yam (Dioscorea trifida), as possible health-promoting ingredient in bread making, in the state of Amazonas. Thus, we determined the centesimal composition, energy, and antioxidant activity of purple yam and four formulations of purple yam bread (0%, 10%, 15% and 20%). We also performed an acceptance test and microbiological analysis of the formulations 10%, 15% and 20%. The Kruskal-Wallis ANOVA revealed no significant differences for the parameters of the centesimal composition and energy of the four formulations, except for lipid. That is, in the process of purple yam bread making, an addition of purple yam in natura up to 20%, instead of wheat flour in ordinary bread (0%), can be made with no effect on the diet s energy, since their chemical composition are similar. By the DPPH method, the samples of purple yam revealed a high antioxidant activity, with values exceeding 70%. The three purple yam breads showed some antioxidant activity with the maximum values above 40%. The LPO method confirmed the antioxidant activity in purple yam and in purple yam breads. In both methods (DPPH and LPO), the antioxidant activity increased as the ratio of purple yam tubers, in substitution of wheat flour, was incorporated in the breads. The Friedman ANOVA was applied to compare the three formulations of purple yam breads; a significant difference only in the attribute color was revealed in the acceptance test. The 20% bread received the best evaluation; the more purple yam in the breads, the higher was the average score. Considering that, for the other sensory attributes, there were no preference differences detected among the breads, they can be considered approved. The results suggest the feasibility of purple yam bread consumption, and its possible use as a health-promoting food. / O objetivo desse estudo foi avaliar o potencial do cará-roxo (Dioscorea trifida) no estado do Amazonas como ingrediente funcional na fabricação de pães. Desse modo, foram determinadas a composição centesimal, valor calórico, e atividade antioxidante do cará-roxo e de quatro formulações de pães de cará-roxo (0%, 10%, 15% e 20%). Foram realizados também teste de aceitação e análise microbiológica das formulações 10%, 15% e 20%. A ANOVA de Kruskal-Wallis não revelou diferença significante para os parâmetros da composição centesimal e valor calórico das quatro formulações, a exceção do lipídio. Isto é, na fabricação de pão de cará-roxo, uma adição de cará-roxo in natura até 20%, em substituição à farinha de trigo no pão comum (0%), pode ser feita sem afetar o valor calórico da dieta, uma vez que a composição centesimal entre os pães é semelhante. As amostras de cará-roxo revelaram uma elevada atividade antioxidante pelo método de sequestro de radicais livres (2,2-difenil-1-picrilhidrazila-DPPH), com valores superiores a 70%. Os pães de cará-roxo (10%, 15% e 20%) apresentaram certa atividade antioxidante com os valores máximos acima de 40%. O método da lipoperoxidação (LPO) confirmou a atividade antioxidante no cará-roxo e nos pães de cará-roxo. Em ambos os métodos (DPPH e LPO), a atividade antioxidante aumentou na proporção em que os tubérculos do cará-roxo foram incorporados ao pão, em substituição à farinha de trigo. A ANOVA de postos de Friedman aplicada para comparar as três formulações de pães de cará-roxo, no teste de aceitação revelou diferenças significantes apenas para o atributo cor. O pão a 20% apresentou uma melhor avaliação. Quanto mais cará-roxo nos pães, maior a nota média obtida. Considerando que, para os demais atributos sensoriais não foram detectadas diferenças de preferência entre os pães, estes podem ser considerados aprovados. Os resultados sugerem a viabilidade do consumo de pão à base de cará-roxo, e seu uso como alimento funcional.

The yam (Dioscorea cayennensis Lam.) is an important staple crop in the Northeast region of Brazil, mainly in the states of Alagoas, Pernambuco, and Paraíba, the highest producing areas in the region. The crop is affected by pathogens that reduce yield and leaf blight, caused by the fungus Curvularia eragrostidis, can cause considerable crop losses. In the socio-economic context in which this crop is placed, the use of resistant varieties is the most effective control strategy. However, for this strategy to be successful, knowledge of the genetic variability of the pathogen is required. Samples of infected yam leaves were collected in 2005 and 2008, from fields in Chã Preta, Paulo Jacinto, and Viçosa and 73 isolates were obtained. Based on morphological characteristics all isolates were identified as C. eragrostidis. All isolates were pathogenic to yam and there were differences in the values of area under the disease progress curve (P= 0.02). When different isolates were paired in culture, mycelia compatibility in the majority of pairings. Similarity and phylogenetic analyses supported the identification of the species associated to yam leaf blight. The AFLP markers were used to investigate the genetic structure of the population of C. eragrostidis. Gene diversity was high (Ht = 0.31) and there was low differentiation between populations (Gst = 0.06). The population was not structured according to geographical origin. The genetic variability within populations of C. eragrostidis was high. / Fundação de Amparo a Pesquisa do Estado de Alagoas / O inhame (Dioscorea cayennensis Lam.) é cultura importante no Nordeste do Brasil, principalmente nos estados de Alagoas, Pernambuco e Paraíba, que se destacam como os maiores produtores. A cultura é afetada por patógenos que reduzem a produtividade. A queima das folhas, causada pelo fungo Curvularia eragrostidis, pode causar perdas significativa de produção. Considerando o contexto sócio-econômico no qual se insere a cultura do inhame, o plantio de variedades resistentes é a estratégia mais adequada de controle da queima foliar. Contudo, o sucesso desta estratégia depende, entre outros fatores, do conhecimento da variabilidade genética do patógeno. Nos anos de 2005 e 2008, coletaram-se amostras de folhas afetadas nos municípios de Chã Preta, Paulo Jacinto e Viçosa e 73 isolados foram obtidos e baseado em características morfológicas, foram identificados como C. eragrostidis. Todos os isolados utilizados no teste de patogenicidade foram patogênicos e houve variação quanto aos valores de AACPD ( P=0,02). Quando diferentes isolados foram pareados em meio de cultura, a maioria mostrou reação de compatibilidade micelial. Análises de similaridade e filogenéticas confirmaram a identificação da espécie associada à queima foliar do inhame. O marcador molecular AFLP foi utilizado com o objetivo de determinar a estrutura genética da população de C. eragrostidis. A diversidade gênica total foi alta (Ht =0,31) com baixa diferenciação entre as populações (Gst = 0,06). Não foi detectada estruturação da população conforme os municípios. A variabilidade genética dentro das populações de C. eragrostidis estudada foi alta.

Submitted by (lucia.rodrigues@ufrpe.br) on 2017-03-17T13:55:35Z No. of bitstreams: 1 Isadora Fernandes de Franca.pdf: 1420687 bytes, checksum: 6cec52a0fb3778ca5533af6c71262265 (MD5) / Made available in DSpace on 2017-03-17T13:55:36Z (GMT). No. of bitstreams: 1 Isadora Fernandes de Franca.pdf: 1420687 bytes, checksum: 6cec52a0fb3778ca5533af6c71262265 (MD5) Previous issue date: 2011-02-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The yam (Dioscorea spp.) has great social importance for the Northeast region of Brazil, due to the excellent nutritional quality and energy of their tubers and very useful for human alimentation. Leaf-spots on white yam, caused by the fungus Curvularia eragrostidis, is responsible for damage to yam in northeast Brazil, mainly in the states of Paraíba and Pernambuco. The aim of this study was to analyze the population structure of isolates of C. eragrostidis pathogenic to yam, D. cayennensis, in the states of Alagoas, Pernambuco and Paraiba, and to study the phylogenetic relationships of these with other species in the genus Cochliobolus. In the first study, 151 isolates were obtained from leaves of yam, which were analyzed the sequences of part of the ITS region and -tubulin gene and gpd and the profiles of DNA with ISSR. It was observed that the DNA sequences had no variation, and ISSR data showed the presence of six haplotypes. The pathogen population is characterized by low genotypic diversity, predominance of one or two genotypes evenly distributed, the predominance of asexual reproduction, and the presence of genotypic flow between the regions of cultivation. In the second study, it was conducted phylogenetic analysis sequences of 81 isolates of species of the family Pleosporaceae using the methods of maximum likelihood and Bayesian inference. The 16 isolates of C. eragrostidis from yam analyzed are related to the genus Cochliobolus species which has smaller conidia and they are phylogenetically closer to the species C. clavata, C. brachyspora, C. oryzae and C. intermedia. / A cultura do inhame (Dioscorea spp.) apresenta grande importância socioeconômica para a região Nordeste do Brasil, devido à excelente qualidade nutritiva e energética de suas túberas e a utilidade para a alimentação humana. A queima das folhas, conhecida também como pinta preta, causada pelo fungo Curvularia eragrostidis, é responsável por grandes prejuízos à cultura do inhame no Nordeste brasileiro, principalmente nos Estados da Paraíba e Pernambuco, que são os maiores produtores. Este trabalho teve como objetivos analisar a estrutura populacional de isolados de C. eragrostidis patogênicos ao inhame, D. cayennensis, nos estados de Alagoas, Pernambuco e Paraíba, bem como estudar as relações filogenéticas destes com as demais espécies do gênero Cochliobolus. No primeiro estudo, foram obtidos 151 isolados, dos quais foram analisados as sequências de parte da região ITS, e dos genes -tubulina e gpd e os perfis de DNA com marcadores ISSR. Observou-se que as sequências de DNA não apresentaram variabilidade, e os dados de ISSR mostraram a presença de seis haplótipos. A população do patógeno é caracterizada por baixa diversidade genotípica, predominância de um ou dois genótipos uniformemente distribuídos, predominância de reprodução assexual, presença de fluxo genotípico entre as regiões de cultivo. No segundo estudo, foram realizadas analises filogenéticas de sequências de 81 isolados de espécies da família Pleosporaceae, através dos métodos de máxima verossimilhança e inferência bayesiana. Os 16 isolados de C. eragrostidis de inhame analisados estão relacionados com espécies do gênero Cochliobolus que apresentam conídios menores e mais próximos filogeneticamente de C. clavata, C. brachyspora, C. oryzae e C. intermedia.

Les tubercules de Dioscorea dumetorum (Kunth) pax sont une importante source de<br />nutriments et d'énergie. Stockés dans les conditions qui prévalent en milieu tropical, ils<br />subissent un phénomène de durcissement caractérisé par la perte de l'aptitude à ramollir pendant la cuisson. Ce travail a été réalisé dans le but de déterminer les mécanismes de durcissement post-récolte des tubercules, d'évaluer les modifications physico-chimiques au cours du stockage et de rechercher les conditions de pré-traitement des tubercules durcis en vue de leur transformation en une farine utilisable dans des formulations alimentaires. Les résultats obtenus ont montré que le durcissement des tubercules de D. dumetorum s'effectue suivant un mécanisme multiple qui inclut l'hydrolyse du phytate comme contributeur minimal de la difficulté-à-cuire et la perte en polyphénols totaux via le mécanisme de lignification comme contributeur majoritaire. Ce durcissement a été dissocié en deux composantes, réversible et irréversible, qui ont été respectivement associées au phytate et aux polyphénols totaux. La modélisation du phénomène de durcissement a montré que la vitesse de la réaction du durcissement irréversible est plus dépendante de la température et de l'humidité relative que celle du durcissement réversible. Le stockage des tubercules de D. dumetorum dans les conditions qui prévalent en milieu tropical (19-28°C, HR 60-85%), a entraîné une diminution significative (P ´ 0,05) des facteurs<br />antinutritionnels (polyphénols totaux, tannins, phytate, oxalates, inhibiteurs de trypsine et d'Α-amylase) et une augmentation des propriétés fonctionnelles des farines (capacité<br />d'absorption d'eau, indice de solubilité à l'eau, capacité d'absorption d'huile, indice<br />hydrophile-lipophile, plus petite concentration gélifiante, capacité de gonflement de la<br />pâte), exception faite sur la densité de la pâte. La variation des différents paramètres<br />évalués s'est effectué en deux principales phases, entre les jours 2 et 21 puis entre les jours 28 et 56. La germination des tubercules ayant été enregistrée après 28 jours de stockage, il a été suggéré que le durcissement post-récolte et la germination influencent les paramètres physico-chimiques des tubercules. Si le trempage préalable des tubercules durcis de D. dumetorum dans des solutions de NaCl ou de kanwa a permis une augmentation significative du taux de ramollissement du tubercule pendant la cuisson, il ne permet pas de surmonter totalement le durcissement des tubercules. Le pré-traitement au kanwa a entraîné une variation significative (P ´ 0,05) des propriétés fonctionnelles des farines de D. dumetorum ainsi qu'une amélioration de la qualité des protéines et de la biodisponibilité in vitro des sucres. Le rouissage naturel des tubercules durcis comme méthode de prétraitement quant à lui a permis d'obtenir un ramollissement total des tubercules après 7 jours de fermentation naturelle et une réduction significative (P ´ 0,05) des facteurs antinutritionnels. Seule la lignine n'a pas été affectée par la fermentation des tubercules. Les propriétés fonctionnelles des farines ont été significativement affectées par la fermentation des tubercules. De plus, la fermentation a entraîné une augmentation significative (P ´ 0,05) de la teneur en protéine, de la qualité des protéines et de la biodisponibilité in vitro des sucres. L'étude de la gélatinisation a montré que la température de gélatinisation des farines de D. dumetorum est comprise entre 70 et 75°C. La gélatinisation des tranches d'igname suit une cinétique d'ordre 1 de la forme générale ln(1 - Α) = kG.t. La constante de vitesse de gélatinisation (kG) diminue avec la baisse de la température de cuisson et l'augmentation du temps de stockage des tubercules. La fermentation et le traitement au kanwa ont présenté une influence significative sur la vitesse de gélatinisation des tubercules durcis de D. dumetorum. La substitution partielle de la farine de blé par les farines d'ignames-durcies ont montré sur la base des analyses multivariés (ACH et ACP) que le blé et les farines composées blé/igname-durcie traitée au kanwa à tous les taux de substitution utilisé dans cette étude, constituent le même groupe. Les farines composées blé/igname-durcie pourraient être utilisées comme ingrédient de base dans la formulation des bouillies infantiles.

Submitted by Viviane Lima da Cunha (viviane@biblioteca.ufpb.br) on 2016-03-15T13:50:26Z No. of bitstreams: 2 arquivototal.pdf: 794071 bytes, checksum: 5ecdac395218752b8d082f4071ef0d25 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-03-15T13:50:26Z (GMT). No. of bitstreams: 2 arquivototal.pdf: 794071 bytes, checksum: 5ecdac395218752b8d082f4071ef0d25 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-02-19 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The objective of this research is to evaluate the productive characteristics of yam, the percentage of tubers with symptoms of nematode attack on tubers and foliar N as a function of subdivision nitrogen. The experimental delineation that we used was randomized blocks with fifteen treatments with four repetitions. The treatments were represented by the following portions of nitrogen (100% on the plantation; 100% at 60 days after the plantation (DAP); 100% at 90 (DAP); 100% at 120 DAP; 50% on the plantation; and 50% at 60 DAP; 50% on the plantation and 50% at 90 DAP; 50% on the plantation and 50% at 120 DAP; 33% on the plantation and 33% at 60 and 33% at 90 DAP; 33% on the plantation, 33% at 90 and 33% at 120 DAP; 33% at 60, 33% at 90 and 33% at 120 DAP; 50% at 60 and 50% at 90 DAP; 50% at 90 and 50% at 120 DAP; 33% at 60, 33% at 90 and 33% at 120 DAP; 50% at 60 and 50% at 120 DAP; and 33% on the plantation, 33% at 60 and 33% at 120 DAP). Each subdivision there were 40 plants, and they were 1.2 x 0.6 m away, one from each other, and all of them were considered useful. The supplying of nitrogen of 100% at 90 DAP showed the greatest length of tubers that measured 25.33 cm, following the subdivisions of 50% on the plantation and 50% at 120 DAP (25.10 cm). The average mass of commercial tubers was superior only on the subdivision of nitrogen of 33% on the plantation, 33% at 60 DAP and 33% at 90 DAP reaching the maximum value of 2.23 kg. The subdivision of nitrogen of 50% at 60 DAP and 50% at 90 DAP provided the highest total productivity and commercial of tubers, 21.7 and 18.9 t ha-1, respectively. The maximum percentage of tubers with attack symptoms of nematodes (dried bark and thick bark) they were 53% and 94%, respectively, obtained when the nitrogen was applied 100% at 60 DAP and 100% on the plantation. When the nitrogen was divided in 33% at 60 DAP, 33% at 90 DAP and 33% at 120 DAP; and 50% on the plantation and 50% at 90 DAP, we did not observed any tubers with the attack symptoms of nematodes. For the content of N in the leaves, we did not see any difference among the treatments. / O trabalho teve como objetivo avaliar as características produtivas do inhame, a percentagem de túberas com sintomas de ataque de nematóides nas túberas e o teor foliar de N em função do parcelamento de nitrogênio. O experimento foi realizado em blocos casualizados com 15 tratamentos, em quatro repetições. Os tratamentos foram representados pelos seguintes parcelamentos de nitrogênio (100% no plantio; 100% aos 60 dias após o plantio (DAP); 100% aos 90 DAP; 100% aos 120 DAP; 50% no plantio e 50% aos 60 DAP; 50% no plantio e 50% aos 90 DAP; 50% no plantio e 50% aos 120 DAP; 33% no plantio, 33% aos 60 e 33% aos 90 DAP; 33% no plantio, 33% aos 90 e 33% aos 120 DAP; 33% aos 60, 33% aos 90 e 33% aos 120 DAP; 50% aos 60 e 50% aos 90 DAP; 50% aos 90 e 50% aos 120 DAP; 33% aos 60, 33% aos 90 e 33% aos 120 DAP; 50% aos 60 e 50% aos 120 DAP; e 33% no plantio, 33% aos 60 e 33% aos 120 DAP). Cada parcela foi constituída por 40 plantas, espaçadas de 1,2 x 0,6 m, todas consideradas úteis. O fornecimento do nitrogênio 100% aos 90 DAP apresentou o maior comprimento de túberas de (25,33 cm), seguido dos parcelamentos 50% no plantio e 50% aos 120 DAP (25,10 cm). A massa média de túberas comerciais foi superior apenas no parcelamento de nitrogênio 33% no plantio, 33% aos 60 DAP e 33% aos 90 DAP atingindo valor máximo de 2,23 kg. O parcelamento do nitrogênio 50% aos 60 e 50% aos 90 DAP proporcionou as maiores produtividades total e comercial de túberas, 21,7 e 18,9 t ha-1, respectivamente. As máximas percentagens de túberas com sintomas de ataque de nematóides (casca seca e casca grossa) foram 53% e 94%, respectivamente, obtidas quando o nitrogênio foi aplicado 100% aos 60 DAP e 100% no plantio. Quando o nitrogênio foi parcelado 33% aos 60 DAP, 33% aos 90 DAP e 33% aos 120 DAP; e 50% no plantio e 50% aos 90 DAP, não foi observado túberas com sintomas de ataque de nematóides. Para o teor foliar de N não se observou diferenças entre os tratamentos.

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-09-27T12:18:23Z No. of bitstreams: 1 LEILA DE SOUSA NUNES - TESE (PPGEP) 2013.pdf: 2235380 bytes, checksum: 9ba032047657e452dd4da722586c9f08 (MD5) / Made available in DSpace on 2018-09-27T12:18:23Z (GMT). No. of bitstreams: 1 LEILA DE SOUSA NUNES - TESE (PPGEP) 2013.pdf: 2235380 bytes, checksum: 9ba032047657e452dd4da722586c9f08 (MD5) Previous issue date: 2013-07 / Capes / Amidos e féculas são polímeros naturais utilizados em diversos setores industriais, porém, na sua forma nativa podem apresentar restrições quanto a determinadas aplicações sendo necessários alguns processos de modificação para que a utilidade deste polímero na indústria possa ser mais ampla. Além disto, o emprego de polímeros naturais na produção de materiais biodegradáveis tem sido uma alternativa, já que as embalagens, a exemplo dos filmes flexíveis, produzidas com plástico sintético se tornaram problema ambiental, por não serem biodegradáveis. Com esta pesquisa objetivou-se a obtenção de féculas nativas e quimicamente modificadas a partir de diferentes espécies de inhame (Dioscorea alata variedade São Tomé e Dioscorea cayennensis variedade Da Costa) para o desenvolvimento de biofilmes. As féculas dos inhames foram extraídas por meio de trituração com solução de NaOH 0,03 eq.L-1 e secas em estufa com circulação de ar. Foram estudados, assim, o rendimento de extração das féculas nativas, as cinéticas de secagem a 30, 40 e 50 °C, as características físico-químicas e funcionais e o equilíbrio higroscópico nas temperaturas de 20, 30 e 40 °C para as féculas nativas e modificadas. Utilizando a técnica de “casting”, biofilmes com 20 e 30 % de plastificante (glicerol) foram elaborados a partir das féculas nativas e modificadas e caracterizados quanto à estrutura física, solubilidade em água e propriedades mecânicas. Concluiu-se que o processo de secagem das féculas de inhame na temperatura de 50 °C foi mais eficiente que nas demais temperaturas estudadas; com valores de coeficientes de determinação superiores a 99,6 % as equações de Page, de Parry e de Henderson & Pabis se equivalem no que se refere ao ajuste matemático aos dados experimentais da secagem das féculas nativas e modificadas; as féculas nativas e modificadas dos inhames São Tomé e Da Costa apresentaram elevado grau de pureza (91,0 % de amido) com predominância de grânulos com formatos elipsoides e triangulares com tamanhos que variam de 10,34 μm a 48,28 μm; a equação de Smith forneceu melhor descrição dos dados experimentais das isotermas das féculas nativas e quimicamente modificadas de inhame com valores médios de coeficiente de determinação maiores que 95,5 %; os fatores concentração de glicerol, variedade de inhame, tipo de fécula e concentração de fécula, mantêm influência significativa sobre grande parte das propriedades das féculas e, consequentemente, dos biofilmes obtidos a partir delas; a modificação química (hidrólise ácida) acarretou diminuição da sinérese das féculas modificadas em relação às nativas; em comparação com as féculas nativas, as féculas ácido-modificadas de inhame originaram biofilmes menos opacos e mais resistentes à tração; o aumento da quantidade de plastificante (glicerol) nos biofilmes de féculas (nativas ou modificadas) de inhame foi um dos fatores determinantes para a elevação das propriedades opacidade, solubilidade em água e porcentagem de elongação, enquanto essa influência ocorreu de forma contrária para a tensão na ruptura. / Starch is a natural polymer used in various industrial sectors. However, in its native form have restrictions on certain applications, requiring some processing so that the use of this polymer in industry can be wider. Furthermore, the use of natural polymers in the production of biodegradable materials has been an alternative, once the packaging, such as flexible films, produced from synthetic plastics have become an environmental problem because they are not biodegradable. The purpose of the present research is to obtain native and chemically modified starches from different species of yam (Dioscorea alata variety São Tomé and Dioscorea cayennensis variety Da Costa ) to the development of biofilms. The yams were extracted from starch by trituration with NaOH 0.03 eq.L -1 and dried in an air circulating oven. It was determined the extraction yield of native starches, the kinetics of drying at 30, 40 and 50 °C, the physico-chemical and functional properties and the equilibrium moisture at temperatures of 20, 30 and 40 °C for native starches and modified. Using the technique of solvent casting, biofilms with 20 and 30% plasticizer glycerol) were prepared from native and modified starches, and had the physical structure, solubility in water and mechanical properties characterized. The drying process of the yam starch at a temperature of 50 °C was more efficient than the other temperatures. With values for correlation coefficients greater than 99.6%, the equations of Page, Parry and Henderson & Pabis were equivalent as regards the mathematical fit of the drying experimental data both for the native and modified starches. The native and modified starches of yams São Tomé and Da Costa showed high purity (91.0 % starch) with a predominance of granules with ellipsoidal and triangular shapes with sizes ranging from 10.34 to 48.28 μm. The Smith equation provided better description for the experimental data of the isotherms of native and chemically modified starches with average values for the coefficient of determination greater than 95.5 %. Factors such as the glycerol concentration, the variety of yam, starch type and concentration of starch remained a largely significant influence on the properties of starch and, consequently, of biofilms obtained from them. The chemical modification (acid hydrolysis) resulted in a decreased syneresis of modified starches in relation to native. In comparison with native starches, acid modified starches originated less opaque biofilms but more resistant to traction. Increasing the amount of plasticizer (glycerol) in biofilms starch (native and modified) yam was one of the determining factors for the increase in opacity properties, water solubility and elongation, while decreasing tension at break.

Submitted by Mario BC (mario@bc.ufrpe.br) on 2016-12-05T12:34:11Z No. of bitstreams: 1 Gisely Santana de França.pdf: 805870 bytes, checksum: df58123076789cb14b94920cb48377b4 (MD5) / Made available in DSpace on 2016-12-05T12:34:11Z (GMT). No. of bitstreams: 1 Gisely Santana de França.pdf: 805870 bytes, checksum: df58123076789cb14b94920cb48377b4 (MD5) Previous issue date: 2016-09-14 / The yam (Dioscorea cayennensis Lam.), Also called yam-the-coast or yams-the-coast belongs to Dioscoreaceae family. This culture is affected by various diseases, the green rot one of the most important, as it causes loss of biological deterioration of tubers during transport and storage. It is caused by the fungus Penicillium sclerotigenum. To control the disease is recommended chemical treatment with fungicides based on benomyl or thiabendazole. However, chemical control induces resistance, and contaminates the environment with the need for alternatives to control. Biological control becomes a promising alternative with considerable success in the control of diseases pre and post-harvest. Among the antagonists used in biological control are the yeast. Thus, the aim of this research was to select yeast isolates and evaluate these as the biocontrol mechanisms. Yeasts were obtained from fragments of leaves, tubers and healthy yam. The P. sclerotigenum isolates used in the pathogenicity and biocontrol tests were isolated from tubers with typical symptoms of the disease. The pathogenicity test was conducted with ten isolated, and the isolated PES 02, the most aggressive and selected for the biocontrol assay. In selecting yeast fifteen isolates were highlighted by reducing the average lesion diameter, being positive for killer toxin, producing volatile compounds and biofilm production. This result supported the biocontrol test, which stood out as the green yams rot biocontrol agents the yeast LEV 02 and LEV 09. These two yeasts were evaluated for resistance induction in tubers through the production of enzymes ascorbate peroxidase (APX ) and catalase (CAT). A variation in enzyme levels in the treated tubers with the pathogen and yeast was verified; when compared to the checks, the pathogen treated only with sterile distilled water. Yeasts have shown potential biocontrol, being a tool for biological control of P. Sclerotigenum in yam. / O inhame (Dioscorea cayennensis Lam.), também denominado de inhame-da-costa ou cará-da-costa pertence à família Dioscoreaceae. Esta cultura é acometida por várias doenças, sendo a podridão verde uma das mais importantes, pois ocasiona perdas por deterioração biológica das túberas durante o transporte e armazenamento. Tendo como agente etiológico Penicillium sclerotigenum. Para o controle da doença é recomendado o tratamento químico, com fungicidas à base de benomyl ou thiabendazol. No entanto, o controle químico induz resistência, e polui o meio ambiente, havendo a necessidade de alternativas para o controle. O controle biológico torna-se uma alternativa promissora com considerável sucesso no controle de doenças de pré e pós-colheita. Dentre os agentes antagonistas utilizados no controle biológico estão às leveduras. Sendo assim, o objetivo da pesquisa foi selecionar isolados de leveduras e avaliar quanto aos mecanismos de biocontrole. As leveduras foram obtidas, de fragmentos de folhas, e túberas sadias de inhame. Os isolados de P. sclerotigenum utilizados nos testes de patogenicidade e biocontrole foram isolados de túberas com sintomas típicos da doença. O teste de patogenicidade foi realizado com dez isolados, sendo o isolado PES- 02, o mais agressivo e selecionado para o teste de biocontrole. Na seleção de leveduras, quinze isolados se destacaram, reduzindo o diâmetro médio da lesão, sendo produtoras de toxina killer, compostos voláteis e produção de biofilme. Este resultado subsidiou o teste de biocontrole, no qual se destacaram as leveduras LEV 02 e LEV 09 como agentes de biocontrole da podridão verde do inhame. As duas leveduras foram avaliadas quanto à indução de resistência em túberas através da produção das enzimas ascorbato peroxidase e catalase. Foi verificada uma variação nos níveis de enzimas nas túberas tratadas com o patógeno e as leveduras; quando comparada com as testemunhas, tratadas apenas com o patógeno e água destilada esterilizada. As leveduras demonstraram potencial de biocontrole, sendo uma ferramenta para o controle biológico do P. sclerotigenum no inhame.